Know the difference between a troffer and a downlight

It is easier and less expensive to change a lamp than a fitting, so make sure you know which fittings you have in your building.

Troffers

Troffers are recessed light fittings that are square or rectangular and usually installed in suspended tiled ceilings. Troffers can have either prismatic diffusers or low glare louvres. The louvre types can cause the ceiling and upper walls to appear dark, so be careful how you use them.

Downlights

Downlights are generally round or square and recessed into the ceiling, but can also be surface-mounted. Some include an open reflector and/or a shielding device/diffuser. Generally the larger the aperture (or opening), the more efficient the downlight will be. Downlights that contain specular reflectors (built in reflective surfaces designed to direct light in a precise direction) can cause the ceiling and upper walls to appear dark, so be careful how you use them.

Linear pendant

Linear pendants are suspended luminaires that typically distribute some light upwards. They can have either prismatic diffusers or low glare louvres. The downside to these louvres is the fact there is not always a transparent upper lamp cover, so the luminaire could be more likely to collect dust, reducing its effectiveness. Care should be taken with selection.

Battens

Most battens are fitted with fluorescent lamps for use in commercial and industrial environments. Designed as surface-mounted or pendant units, they may have plastic covers (diffuser) or metal reflectors around the tubes, are easy to install and can be used separately or as strip lighting. Suitable housings ensure that light is directed as required and glare is kept to a minimum.

Low bay

Low bay light fittings appear as square or rectangular boxes housing high intensity discharge lamps. Mounted horizontally at low heights (4-6 metres), these are typically used in industrial, sporting and public concourses.

High Bay

High Bay light fittings are typically sold in pendant format with a single lamp vertically mounted. Like low bay fittings they house high intensity discharge lamps although they can be mounted higher (8-10 metres). Most High Bay fittings are found in industrial, sporting and public spaces.